Magnet wire insulating machinery



J. J. KEYES MAGNET WIRE INSULATING MACHINERY Nov. 7, 1939.

Filed Feb. 20, 1936 3 Sheets-Sheet l Fig.

INVENTOR John J Ka /es.

BY fMZ.

ATTORNFY J. J. KEYES Nov. 7, 1939.

MAGNET WIRE INSULATING MACHINERY 3 Sheets-Sheet 2 8 Q v W5 3 2 Filed Feb. 20, 1936 V/ a a a 7/ m m w INVENTOR fa/m J. Keyes BY F a.

WITNESSES: W M @m ATTORNEY KEYES Nov. 7, 1939.

3 Sheets-Sheet 5 Filed Feb. 20, 1956 I I l/lll/t WITNESSES: W 6% Z Patented Nov. 7, 1939 UNITED STATES PATENT OFFEE I John J. Keyes, Pittsburgh, Pa, assignor to Westinghouse Electric & Manufacturing Company,

East Pittsburgh, Pa,

sylvan a a corporation of Penn- Application February 20, 1936, Serial No, 64,878

2' Claims.

My invention relates, generally, to friction clutches and, more particularly to improvements in the wrapping head structure for wrapping machines.

Wrapping heads of conductor-wrapping machines are designed to operate at comparatively high speeds. During such operation, the wrapping material is supplied to the conductor from a spool of wrapping-material mounted concentric of the head and the conductor being wrapped. The spool for supplying the wrapping material to the conductor is so mounted that it may rotate with reference to the fiyer support. In operation, that is, conventional operation, the spool will have a speed always somewhat greater than the fiyer. The speed differential will depend on the size of the spool, namely, the quantity of paper or other wrapping material on the spool.

To prevent a too free relative movement between the fiyer and the spool, the spool is frictionally restrained. The restraining force will determine the tension with which the material is wrapped on the conductor.

A full spool naturally has the covering material removed therefrom at a much greater distance from its center and the moment arm is much greater. A constant frictional restraining force will thus by no means produce a constant tension in the Wrapping material. Further, an empty spool is much less in weight so that the frictional force varies with the size, or weight, of the spool. The tension in the material, in the absence of my invention, thus varies with the weight and the size or diameter of the spool for a given coefiicient of friction.

One object of my invention is to maintain constant tension in the material being wrapped on a core.

Another object of my invention is to provide for varying the frictional restraining force of friction clutch means, to provide a constant driving torque substantially independent of clutch pressure.

A still further object of my invention is to provide for a transmission of a substantially constant force at varying radii of a driven portion of a clutch independent of the pressure between the clutch members.

A more specific object of my invention is to maintain substantially constant tension in a strand of material being unwound from a spool regardless of the diameter of the spool from which it is wound.

Other objects and advantages of my invention will become more apparent from a study of the following specification when considered in conjunction with the accompanying drawings, in which:

Figure 1 is a vertical sectional View of my invention and showing a spool support of a core wrapping head for a wrapping machine such as is disclosed in my copending application for Letters Patent entitled Stop control means for core wrapping machines, filed November 5, 1935, Serial No. 48,329;

Fig. 2 is a vertical sectional view like the showing in Fig. 1 but illustrating a modification of my invention;

Fig. 3 is a vertical sectional view of another modification of my invention; and

Figs. 4 and 5 are a plan view and side view, respectively, of a still further modification of my invention, and wherein parts are broken away to better show some of the details.

Referring to Fig. 1, reference character I designates the base of a fiyer or wrapping head and thus constitutes the rotating support for the spool 2 of wrapping material that is used in connection with the application of insulating material to a core or electrical conductor. The spool is merely indicated in dotted lines because the spool itself does not constitute part of my invention.

The base i is keyed to the hollow shaft 3 and thus rotates with the shaft. The core to be wrapped passes through this hollow shaft 3 and is provided with the wrapping material at the top of the fiyer by a suitable wrapping head not constituting part of this invention.

The spool itself rests on a sleeve i mounted on anti-friction bearings as the ball bearings 5. The race 6 of the ball bearings is screw threaded to a second sleeve l keyed to the hollow shaft 3. As indicated at 8, the keyway is loose to thus permit free vertical movement of the sleeve 7 and the parts as sleeve d, ball bearings 5 and race 6 carried thereby.

The lower end of the sleeve 4 is provided with a table 9 for the spool 2. The lower surface is designed to be a friction member it and thus constitutes one friction face of the clutch mechanism. The other friction member E2 of the clutch mechanism ii is disposed adjacent the member is and normally the faces of these members are in engagement so that table 9 tends to rotate with the base l3 securely holding the lower friction member it. The friction member i2 may be rubber, fabric, or any other suitable material having a desired coefficient of friction.

The base I3 is keyed to the shaft 3, as shown rial.

at I5, and thus is positively driven by the shaft 3. A sponge rubber washer I4 is disposed between the base I3 and the main base or support I so that base I3 may move vertically with varying weights of the spool 2.

While the table 9 tends to rotate with the base I3, it should be remembered, as hereinbefore explained, that the spool, and thus the sleeve 4, as the material is withdrawn during the core wrapping operation, rotates faster than base I3 and is restrained in such relative rotation by the frictional force of the two clutch faces, that is, the friction members I0 and I2. The force of friction determines the tension with which the material is applied to the core. However, the effective tension in the wrapping material is complicated by the variations in weight of the spool, the size, that is, the varying moment arm of the spool as the material is withdrawn, and the change in relativespeed between the base I3 and table 9 resulting from the variations in the diameter of the spool.

The best product, namely the best insulated conductor is produced if the material is applied to the conductor with uniformtension. Furthermore, the material is very much less likely to break when applied with uniform tension, thus eliminating frequent stopping of the machine and also eliminating considerable wasting of mate- One of the objects of my invention, as hereinbefore stated, is to provide for a uniform tension in the wrapping material taken from the spool 2.

In attempting to get uniform tension in the wrapping material for a conductor with the devices of the prior art from a full spool of insulation to an empty spool of insulation, it has been found, for conventional sizes of spools when the proper friction washers for the clutch mechanism as I I had been chosen to give current tension for a full tube or spool of insulation, that the tension was far too great when the insulation is used up to a certain point.

To obviate such improper operation as just pointed out, I position a spring I6 between the base I3 and the sleeve I. The lower end of the sleeve I is threaded to receive a nut II, which nut constitutes an adjustable stop or operating ledge for the spring It. The proportion of the weight of the spool and sleeve I that spring It supports may thus be adjusted at will. In Fig. l, the parts are shown in a position such as they would occupy when no insulation spool is on the table 9. Even an empty spool will add sufficient weight to table 9 and sleeve 4 that members It] and. I2 will operatively engage.

To more clearly describe the useful features of the spring and the adjusting means therefor, let it be assumed no spring is present and that the weight of the full spool and the other elements 4, 5, 6, I and 9 acting on the members 56 and i2 is equal to 1.4 pounds and that the weight of the empty tube or spool and the same elements 4, 5, 6, I and i] acting on surfaces ID and I2 is .4 pound. The ratio of pressures from a full spool to an empty spool is thus 3.5 to 1.

When the spring is used, the pressure at the members I0 and I2 may be decreased by an amount determined by the compression of spring I6. If the spring raises .2 of a pound of the total weight, then the pressure on surfaces or members I 0 and I2 will be 1.2 pounds for a full spool and .2 pound for an empty spool. The ratio of pressures From this analysis it is apparent that as the moment arm decreases the force of friction decreases in such a manner to maintain the tension in the material substantially constant.

In the modification shown in Fig. 2 like elements are designated by the same reference charaeters. In this modification the control is somewhat more sensitive. The arrangement of the parts is of particular utility when rather fragile insulating material is used. In this Fig. 2, the reference character 22 designates a friction member of a comparatively high coefficient of friction whereas the friction ring 2i represents a graphite friction surface having a much lower coefficient of friction than the friction member 22.

Spring I6 in this modification acts on the bottom of the slidably mounted base 20. The parts are shown in inoperative position; however when a full spool is placed on table 9, friction members I!) and 22 are in engagement and the table 9 is restrained with a considerable force, but since the moment arm is large, the tension will not be in proportion to the increased length of the moment arm but will represent some given desired value. As the size of the spool decreases, a greater and greater proportion of the weight of the spool and retaining sleeve 4' is carried by the friction surface 2!. The restraining force thus decreases.

Eventually, when the spool is nearly empty the parts will be in a position substantially as shown. The graphite friction ring 2I alone will contact friction member I0, thus restraining the sleeve i with a small force, but since the diameter of the spool is small, the tension will remain substantially constant. e

The sleeve 4 is shown as mounted for rotation directly on shaft 3, but it is clear the ball bearings shown in Fig. 1 can also be used with the modification shown in Fig. 2. The modification shown in Fig. 2 is of special utility where the force of friction is to have a greater range than for the structure shown in Fig. 1.

Referring to Fig. 3, the spool is mounted in fixed relation to the spool support 32 having the supporting sleeve 33, which sleeve is disposed to rotate freely on ball bearings 34. The races 35 for the ball bearings are mounted on a sleeve 36 having vertically slidable movement on the spindle 3 in the guideways 37. A portion of the weight of the sleeve 36 is supported by the spring 38.

As generally hereinbefore pointed out, the spool support 32 is restrained in its rotation relative to face plate 30 by friction rings. These rings comprise a graphite or similar ring 39 having a low coefficient of friction and a fiber ring 40 having a higher coefficient of friction. These two rings 39 and 40 coact with the friction surface 4!. Spring 42 is disposed between the rings 39 and 40 with the result that they tend to be moved out of a common plane.

The friction rings 39 and 4f! coact with the friction surface II to restrain relative rotation between the spool support 32 and the face plate 30; however, the operation is not just such a simple effect. For a heavy or full spool of insulation, the springs 38 and 42 coact in such a man nor that friction ring 39 is moved vertically downward by an amount sufficient to cause coaction between the ring 4!! and surface II. In other words, a full spool will be restrained by a larger force of friction than a nearly empty spool.

A full spool naturally has the covering material removed therefrom at a much greater distance (iii from its center of rotation. The moment arm is much greater. If the force of friction is ircreased proportional to a function of the spool diameter, by a proper spring adjustment and otherwise proper design, the tension in the covering material may be kept substantially constant regardless of the size or weight of the spool.

While springs 38 and 42 do coact, spring 38 is primarily used to compensate for the weight of sleeves m; and 36 and the spool support 32. The tension the covering material can be effectively controlled by a proper adjustment of spring 42 or by a proper selection of the size or spring effect of the spring Malone, provided the total Weight variation of the spool and-elements 32, 33 and 35 have the proper value in relation to spring 42 and the differential effect of the friction rings 38 and Ni.

Since spring 52 produces a differential movement between the surfaces 39 and it], the force of friction between the spring support 32 and face plate 3% can be made a function of the moment arm of the force withdrawing the core covering, the weight of the spool, and the relative speed of the parts. That is, the force of friction is made a function of the factors stated with the result that the tension with which the material or covering is applied remains substantially constant, thus improving the final product. Applying the material at constant tension eliminates frequent breaks of the material and the consequent need for frequent stopping of the machine.

If the face plate 30 is stopped for any reason, the spool and sleeve 33 will spin and thus tangle a considerable quantity of wrapping material. The force of frictionat surface M and'friction rings 39 and lfl is not of sufficient magnitude to prevent this. As a matter of fact, the strength of the wrapping material near the desirable tension with which it is applied does not permit of such magnitude of frictional force.

With the machines at present in use, that is, machines of the prior art not using my contribution to the art, frequent stops are necessary during the unwrapping of a single spool to adjust the tension of the material. With my device, the friction force between the face plate 30 and the spool support 32 is automatically varied so that the tension in the wrapping material remains substantially constant during the complete unwinding of a spool.

To prevent tangling of the wrapping material when the face plate so is stopped, an electromagnetic coil is mounted below the spool support.

This coil is so interconnected with a source of elec trical energy, preferably of low voltage, that it ecomes energized when the face plate 25 is retarded or decelerated during stopping of the machine. The electromagnetic means do not constitute part of this invention and are shown only in Fig. 3 to illustrate the complete structure of an existing successful machine utilizing the contributions that I have made to the art.

Fig. 4. represents a somewhat different means for restraining the movement of the spool with reference to the spool support, so that substantially constant tension is maintained on the wrapping material. In this instance, the face plate 53 is mounted to be driven in a counter-clockwise direction by the hollow shaft 3. A Weight mounted on the arms 50, engages the spool support 53 to drive it in a counter-clockwise direction. In practice the spool support 53 rotates faster than the arms 56, so that no positive drive is in fact effected by the weight 5!, but reverse movement is prevented by the dogs actuated by the weight.

The spool support comprises an aluminum or oil er metal disk 53 disposed between a pair of poles of a permanent electromagnet 54 his magnet constitutes one arm of a bell crank lever 55 pivoted at 56. The other arm 5? has a roller 58 adapted to engage the outer periphery of the spool 2. When the spool is full the speed of disk 53 will be comparatively small but if the restraining force is made a function of the size of the spool and the speed of the spool, a restraining force can be readily secured which will maintain constant tension on the wrapping material withdrawn from the spool 2. This restraining effect is accomplished by the magnetic breaking effect of the permanent magnet 54 coacting with the metal disk 53.

When the tube is full the speed is low but the magnet is disposed at a considerable distance from the center of rotation of the disk 53, so that the metal disposed between the pole pieces passes these pieces at a considerable speed and since the restraining force is proportional to the speed, the tension will be maintained at a substantially constant value depending upon the design and dimensions of the bell crank lever and characteristics of the permanent magnet.

I am, of course, aware that others, particularly after having had the benefit of the teachings of my invention, can devise other clutch means for providing a restraining force for the spool support to thus control the tension in the material being unwrapped from the spool disposed on the spool support. I wish to be limited only by the appended claims and the scope of the pertinent prior art.

I claim as my invention:

i. In a serving apparatus for a core wrapping machine, in combination, a vertical hollow shaft, a core to be wrapped passing through the shaft, a friction ring secured to the shaft, 2. second friction ring, having a lower coefficient of friction than the first friction ring, slidably mounted on the shaft; resilient means between said rings to cause the second ring to move out of the plane of the first friction ring; a third friction ring loosely mounted on the shaft fricticnally engaging the first two rings and designed to support the wrapping material, which wrapping material is removed from the second ring at lesser and lesser moment arms as the amount of material on the second ring decreases, resilient means for decreasing the normal pressure, and thus the frictional effect, between the rings, and means adapted to change the frictional effect between the rings as the resilient means decreases the normal pressure between the rings.

2. In a serving device for a core wrapping ma chine, in combination, a hollow shaft vertically disposed and through which the core to be wrapped passes, a pair of concentric friction rings having friction surfaces, means for moving rings axially of each other so that the friction surfaces of said rings may be moved out of a common plane, said friction surfaces having different coefficients of friction, a material support mounted on the shaft, having a friction surface at its underside, adapted to engage the friction surfaces of the rings, a spring between one of said rings and the material support adapted to support nearlythe entire weight of the material. support Without the material thereon, said means for ax ally moving the rings being acted upon by the weight of one of the rings, the spring, the material support, and the material on the support whereby the force of engagement of the friction surface at the underside of the material support with the friction surfaces of the rings ismade a function of the weight of the material on the support and the relative position of all the friction surfaces, whereby the feeding characteristics of the material to the core may be controlled.

3. A clutch mechanism, in combination, a rotatable shaft; a pair of friction surfaces disposed to rotate with the shaft facing in the same direction, one surface having a lower coefficient of friction than the other; a spring for biasing the friction member having the lower coefiicient of friction out of the plane of the other friction surface and in a direction toward which both surfaces face; and a third friction surface loosely mounted on the shaft and facing the pair of friction surfaces, said third friction surface being acted upon toward the pair of friction surfaces by forces that vary from a given maximum to a given m nimum, whereby the third friction surface is driven by the pair of friction surfaces by a total force of friction that varies inversely with the variations of the forces acting on the third friction surface.

4. A clutch mechan sm, in combination, a retatable vertically disposed shaft; a friction member mounted on the shaft for rotation with the shaft; a second friction member having a lower coefficient of friction than the first friction member mounted on the shaft for rotation with the shaft but mounted for slidable movement on the shaft; resilient means disposed between said friction members to bias the second friction member to a position not in the same plane normal to the shaft; a third friction member, disposed above said first and second friction members and urged toward them by a force varying from a given maximum to a given minimum, to thus move the second friction member into the plane of the first friction member when the third friction member is acted upon by a predetermined force intermediate the said minimum and maximum forces whereby the third friction member is driven either by both the first and second friction member or by the second only depending upon whether the particular force acting on the third friction member is above or below said predetermined force; and means for exerting a force on the third friction member at varying distances from the axis of the shaft in a plane at right angles to the axis of the shaft the varying distance at which this force acts corresponding generally to the forces acting on the third friction member, whereby the force produced by said last named means is substantially constant.

5. In a serving device for a core wrapping machine, in combination, a vertical hollow shaft; a core to be wrapped passing through the shaft; a friction ring secured for rotation on the shaft; a second friction ring having a lower coefficient of friction; resilient means disposed between the first friction ring and the second friction ring adapted to resiliently hold the second friction ring a relatively small distance above the first friction ring; a third friction ring, rotatable with the shaft but slidably mounted on the shaft, disposed in facing relation to said first two friction rings; and a spool support and spool for wrapping material on the third friction ring; said wrapping material being removed from the spool at lesser and lesser moment arms as the amount of material on the spool decreases.

6. In a'serving device for a core wrapping machine, in combination, a vertical hollow shaft; a core to be wrapped passing through the shaft; a friction ring slidably mounted on the shaft but secured for rotation on the shaft; resilient means upon which said friction ring rests; a second fric-- tion ring having a lower coefficient of friction; resilient means disposed between the first friction ring and the second friction ring adapted to resiliently hold the second friction ring a relatively small distance above the first friction ring; a third friction ring, rotatable with the shaft but slidably mounted on the shaft, disposed in facing relation to said first two friction rings; and a spool support and spool for wrapping material on the third friction ring; said wrapping material being removed from the spool at lesser and lesser moment arms as the amount of material on the spool decreases.

'7. In a serving device for a core wrapping machine, in combination, a vertical hollow shaft; a core to be wrapped passing through the shaft; a friction ring secured for rotation on the shaft; a second friction ring having a lower coefficient of friction; resilient means disposed between the first friction ring and the second friction ring adapted to resiliently hold the second friction ring a relatively small distance above the first friction ring; a third friction ring, rotatable with the shaft but slidably mounted on the shaft, disposed in facing relation to said first two friction rings; resilient means disposed between the third friction ring and the second friction ring; and a spool support and spool for wrapping material on the third friction ring; said last named resilient means being so selected to nearly counteract the combined weight of the third friction ring, spool support, and empty spool, said wrapping material being removed from the spool at lesser and lesser moment arms as the amount of material on the spool decreases, and means for ad justing the effect of said last named resilient means.

- JOHN J. KEYES. 

